Alternative for accepts_nested_attributes_for - maybe virtus

Question

I\'m relatively new to rails and finally found the right way to use accepts_nested_attributes_for.

However, there are some serious resources on the web who

Answer 1

So, the accepted answer just says why accepts_nested_attributes_for is often a good solution, but never actually offers a solution on how to do it. And the example in the linked article will run into problems if you want to make your form accept a dynamic number of nested objects. This is the only solution I've found

https://coderwall.com/p/kvsbfa/nested-forms-with-activemodel-model-objects

For posterity this is the basics, but there's a bit more on the site:

class ContactListForm
include ActiveModel::Model

attr_accessor :contacts

def contacts_attributes=(attributes)
  @contacts ||= []
  attributes.each do |i, contact_params|
    @contacts.push(Contact.new(contact_params))
  end
end
end

class ContactsController < ApplicationController
   def new
      @contact_list = ContactListForm.new(contacts: [Contact.new])
    end
  end

and f.fields_for :contacts should behave like an has_many relationship, and easily handled by your form object.

If Contact isn't an AR model you'll need to spoof persisted? as well.